CN215645032U - Doppler radar four-beam antenna for generating overlapped beams - Google Patents
Doppler radar four-beam antenna for generating overlapped beams Download PDFInfo
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- CN215645032U CN215645032U CN202121148425.9U CN202121148425U CN215645032U CN 215645032 U CN215645032 U CN 215645032U CN 202121148425 U CN202121148425 U CN 202121148425U CN 215645032 U CN215645032 U CN 215645032U
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Abstract
The utility model relates to a Doppler radar four-beam antenna for generating overlapped beams, which comprises a radiation array surface unit and a feed unit; the radiation array surface unit comprises N radiation waveguides which are parallel and uniformly arranged; the feed unit comprises 4 feed waveguides; the 4 feed waveguides are arranged in a pairwise manner; two feed waveguides are arranged on the left side of the radiation array surface unit and feed to the left input end of each radiation waveguide; and the other two feed waveguides are arranged on the right side of the radiation array surface unit and feed the right input end of each radiation waveguide. The antenna reduces the projection area of the wave beam, sharpens the available wave beam to a certain extent, improves the Doppler frequency spectrum purity and further improves the speed measurement precision.
Description
Technical Field
The utility model relates to the technical field of antennas, in particular to a Doppler radar four-beam antenna for generating overlapped beams.
Background
The Doppler radar can automatically, continuously and accurately measure the velocity vector information of the flight carriers such as unmanned planes and the like, the work of the Doppler radar is not limited by geographical and meteorological conditions, and the velocity measurement precision of the Doppler radar is the same in the whole flight. The speed measurement precision of the common Doppler radar can only meet the use requirement of civil aircrafts, and the requirement on the speed measurement precision of a flying carrier is very high and is difficult to meet.
The influence of antenna factors on the accuracy of the Doppler velocity measurement radar is mainly concentrated on that the beam width of an antenna is not narrow enough, so that a section of frequency spectrum with a bandwidth is formed on Doppler frequency shift, and the accuracy of velocity measurement is limited. The conventional doppler radar antenna is contradictory to the improvement of the narrowness of the antenna beam and the antenna aperture, that is, the narrower the beam, the larger the antenna aperture, and therefore, it is difficult to improve the speed measurement accuracy of the doppler radar in an application scene with limited antenna aperture.
The overlapping area of every two overlapped beams is much narrower than the width of the original beam; the doppler spectrum bandwidth in the overlap region is also narrowed, and the velocity accuracy can be improved by using the overlap region. Therefore, in order to realize a beam sharpening function under a limited antenna aperture, improve doppler spectrum purity and improve speed measurement accuracy, the overlapping beam antenna is a demand.
SUMMERY OF THE UTILITY MODEL
In view of the above analysis, the present invention is directed to a doppler radar four-beam antenna for generating overlapped beams to generate overlapped beams, thereby implementing a beam sharpening function under a limited antenna aperture.
The purpose of the utility model is mainly realized by the following technical scheme:
the utility model discloses a Doppler radar four-beam antenna for generating overlapped beams, which comprises a radiation array surface unit and a feed unit;
the radiation array surface unit comprises N radiation waveguides which are parallel and uniformly arranged;
the feed unit comprises 4 feed waveguides; the 4 feed waveguides are arranged in a pairwise manner; two feed waveguides are arranged on the left side of the radiation array surface unit and feed to the left input end of each radiation waveguide; and the other two feed waveguides are arranged on the right side of the radiation array surface unit and feed the right input end of each radiation waveguide.
Furthermore, both ends of each feed waveguide are feed ports; the 4 feed ports of the two upper feed waveguides in the 4 feed waveguides arranged in pairwise rows are respectively used for feeding signals with the frequency of F1; the 4 feeding ports of the two feeding waveguides at the lower layer of the 4 feeding waveguides arranged in two-by-two rows are respectively used for feeding signals with the frequency of F2.
Further, each radiation waveguide comprises a horn section at two ends and a radiation section in the middle; the wide end of the horn section contains 2 feed waveguides arranged in a row, and the narrow end of the horn section is connected with the radiation section; the horn section is used for realizing the transition of a signal from the feed waveguide to the radiation section; the radiating section is used for radiating signals.
Furthermore, the radiation section of the radiation waveguide is a traveling wave slot radiation waveguide with a narrow edge slot; the narrow edge of the waveguide is provided with a plurality of narrow edge cracks with the same length and width and staggered inclination angles, the interval between every two adjacent narrow edge cracks is the same, and the narrow edge cracks are symmetrically distributed on two sides relative to the central line of the radiation waveguide.
Furthermore, the feed waveguide is a traveling wave slot waveguide with a slot at a narrow edge; n narrow-edge slots with staggered dip angles are also formed in the direction of each feed waveguide close to the narrow edge of the radiation waveguide.
Further, the number of the radiation waveguides is 22; the radiation waveguide cavity size is 17mm x 4 mm.
Furthermore, each radiation waveguide is provided with 36 narrow-side slots with staggered dip angles, and the spacing of the radiation slots is 11 mm.
Furthermore, the size of the feed waveguide is 18.75mm × 4mm, and 22 narrow-edge slots with staggered dip angles are formed in the direction of each feed waveguide close to the narrow edge of the radiation waveguide; the feed waveguide slot pitch was 9 mm.
Further, 8 feed ports of 4 feed waveguides are each mounted with a waveguide isolator.
Further, the structural size of the antenna is no more than 400mm × 200mm × 30 mm.
The utility model has at least one of the following beneficial effects:
the utility model changes the beam projection area used by the Doppler radar antenna from the original single beam area to the overlapping area of the beams, reduces the beam projection area, and sharpens the available beams to a certain extent, thereby improving the Doppler frequency spectrum purity and improving the speed measurement precision.
Drawings
The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the utility model, wherein like reference numerals are used to designate like parts throughout.
FIG. 1 is a top view of a Doppler radar four-beam antenna in an embodiment of the present invention;
FIG. 2 is a side view of a Doppler radar four-beam antenna in an embodiment of the present invention;
FIG. 3 is a diagram illustrating four overlapping beams generated by an antenna according to an embodiment of the present invention;
FIG. 4 is a schematic view of a projection of an antenna pattern onto a transmitting surface in an embodiment of the present invention;
fig. 5 is a schematic diagram of a feed structure of an overlapping beam antenna in an embodiment of the present invention.
Detailed Description
The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form a part hereof, and which together with the embodiments of the utility model serve to explain the principles of the utility model.
In an embodiment of the present invention, a doppler radar four-beam antenna for generating overlapping beams is disclosed, as shown in fig. 1 or fig. 2, including a radiation front unit and a feed unit;
the radiation array surface unit comprises N radiation waveguides which are parallel and uniformly arranged;
the feed unit comprises 4 feed waveguides; the 4 feed waveguides are arranged in a pairwise manner; two feed waveguides are arranged on the left side of the radiation array surface unit and feed to the left input end of each radiation waveguide; and the other two feed waveguides are arranged on the right side of the radiation array surface unit and feed the right input end of each radiation waveguide.
Specifically, both ends of each feed waveguide are feed ports; the 4 feed ports of the two upper feed waveguides in the 4 feed waveguides arranged in pairwise rows are respectively used for feeding signals with the frequency of F1; the 4 feeding ports of the two feeding waveguides at the lower layer of the 4 feeding waveguides arranged in two-by-two rows are respectively used for feeding signals with the frequency of F2.
Signals with the frequency of F1 fed by the 4 feed ports of the upper two feed waveguides and signals with the frequency of F2 fed by the 4 feed ports of the lower two feed waveguides are radiated to the ground through the N radiation waveguides; the frequency F1 and the frequency F2 are staggered from each other by a frequency in a certain frequency band, when the antenna radiates outwards through the N radiation waveguides, two directional patterns with different frequencies appear in an antenna radiation field, and because the frequency bands are relatively close to each other, two beams generated by two ports overlap with each other, therefore, when the antenna of the embodiment transmits signals with the frequency F1 and the frequency F2, four beams overlapping with each other in pair are generated, and the projection of the four beams on the ground is shown in fig. 4. Due to the close proximity of the two beams, it is sufficient to consider the ground reflection characteristics to be the same. In the case of corrected drift angle, a position can be found where the frequency at the intersection of the two doppler spectrum envelopes corresponds to a frequency independent of the type of reflecting surface.
More specifically, in order to realize the interaction between the feed waveguides and the radiation waveguides arranged in two rows, as shown in fig. 5, each radiation waveguide includes a horn section at two ends and a radiation section in the middle; the wide end of the horn section contains 2 feed waveguides arranged in a row, and the narrow end of the horn section is connected with the radiation section; the horn section is used for realizing the transition of a signal from the feed waveguide to the radiation waveguide cavity of the radiation section; the radiating section is used for radiating signals.
Preferably, the radiation section of the radiation waveguide is a traveling wave slot radiation waveguide with a narrow edge slot; the narrow edge of the waveguide is provided with a plurality of narrow edge cracks with the same length and width and staggered inclination angles, the interval between every two adjacent narrow edge cracks is the same, and the narrow edge cracks are symmetrically distributed on two sides relative to the central line of the radiation waveguide.
The feed waveguide is a traveling wave slot waveguide with a slot at a narrow edge; n narrow-edge slots with staggered dip angles are also formed in the direction of each feed waveguide close to the narrow edge of the radiation waveguide.
And, waveguide isolators are installed to 8 feed ports of the 4 feed waveguides.
When 1 feed port in 4 feed ports of the two upper feed waveguides is incident or emergent, isolators of 3 feed ports of the two upper feed waveguides have the function of absorbing reverse load;
when 1 feed port in 4 feed ports of the lower two feed waveguides is incident or emergent, the isolators of 3 feed ports of the lower two feed waveguides have the function of absorbing reverse load.
In a specific embodiment of the utility model, the structure size of the doppler radar four-beam antenna generating overlapping beams is not more than 400mm x 200mm x 30 mm.
The radiation array surface unit consists of 22 radiation waveguides, each radiation waveguide is provided with 36 narrow-edge gaps with staggered dip angles and used for radiating electromagnetic energy to space, the space between the radiation gaps is 11mm, and the size of an inner cavity of each radiation waveguide is 17mm multiplied by 4 mm; the amplitude distribution function of the radiation waveguide is weighted according to-20 dB Chebyshev, the inclination angle of each slot is determined according to the weighted result, and the cut-in depth is determined according to the simulated resonance size of each slot.
The feed unit comprises 4 feed waveguides, wherein two feed waveguides are arranged on the left side in a row mode, and the other two feed waveguides are arranged on the right side after being overlapped. The dimensions of the feed waveguide are 18.75mm x 4 mm; 22 narrow-edge gaps with staggered dip angles are also formed in the direction of each feed waveguide close to the narrow edge of the radiation waveguide; the feed waveguide slot pitch was 9 mm.
The feeding frequencies F1 and F2 are 13.325GHz and 13.5GHz, respectively.
The four-beam antenna of the doppler radar of the embodiment can also realize antenna transceiving multiplexing through a time division switching function.
The operation of the overlapping beam antenna of the present embodiment is as follows:
in the antenna time division working system, 8 feed ports are accessed to a transmitting signal in a time division mode.
1) At time T1, the feed port 1 inputs the frequency F1, and the feed port 5 inputs the frequency F2, two beams are generated in the earth quadrant I of the beam projection, one beam is generated by the feed port 1, and the azimuth angle is 1 and the pitch angle is 1; one beam is generated by the feed port 5, azimuth 5, elevation 5. Because the frequency F1 and the frequency F2 are very close, the angle difference between the azimuth angles 1 and 5 and the pitch angles 1 and 5 is very small, and is between 0.5 and 3 degrees, and the control can be realized through design; thus, overlapping beams with mutually irrelevant frequencies are generated, and the projection on the ground generates an overlapping area projection.
2) After the radiation array surface unit radiates signals, the high-frequency receiver can instantly receive echo signals which are projected to the earth quadrant I by the antenna to generate two wave beams, the signal processing extension set extracts frequency spectrum information of a wave beam overlapping region formed by two frequencies, speed calculation is carried out on an azimuth angle and a pitch angle after the wave beams are overlapped through a known port 1 and a known port 5, and the information informs a central control machine of a radar;
3) at time T2, feed port 2 inputs frequency F1, while feed port 6 inputs frequency F2, generating two beams in quadrant II of the beam projection, one beam generated by feed port 2, azimuth 2, pitch 2; one beam is generated by the feed port 6, azimuth 6, elevation 6. Because the frequency F1 and the frequency F2 are very close, the angle difference between the azimuth angles 2 and 6 and the pitch angles 2 and 6 is very small, and is between 0.5 and 3 degrees, and the control can be realized through design; thus, overlapping beams with mutually irrelevant frequencies are generated, and the projection on the ground generates an overlapping area projection.
4) After the radiation array surface unit radiates signals, the high-frequency receiver can instantly receive echo signals which are projected to a ground quadrant II by an antenna to generate two wave beams, the signal processing extension set extracts frequency spectrum information of a wave beam overlapping region formed by two frequencies, speed calculation is carried out on an azimuth angle and a pitch angle after the wave beams are overlapped through a known port 2 and a known port 6, and the information informs a central control machine of a radar;
5) the working principle of the other four feed ports is the same as that of the feed ports 1, 2, 3 and 4, the input frequency is F1, and the projection of the generated four beams on the ground is in an X shape and is symmetrical about the vertical center of the antenna; the frequency input by the feed ports 5, 6, 7 and 8 is F2, the projection of the generated four beams on the ground is also in an X shape, and is also vertically symmetrical with respect to the antenna; with the overlapping beams generated by ports 1 and 5 in the first quadrant, the overlapping beams generated by ports 2 and 6 in the second quadrant, the overlapping beams generated by ports 3 and 7 in the third quadrant, and the overlapping beams generated by ports 4 and 8 in the fourth quadrant.
Therefore, by receiving the overlapped wave beams of the four echoes, the high-frequency receiving system of the radar can extract the frequency spectrum of the wave beam overlapped area, and the frequency spectrum width is 20% -25% narrower, so that the frequency spectrum purity is improved, and the speed measurement precision is greatly improved.
Compared with a common four-beam antenna, the overlapping four-beam antenna can effectively eliminate the influence of the Doppler radar on ground scattering, so that a beam projection area used by the Doppler radar antenna is changed from an original single beam area to an overlapping area of beams, the beam projection area is reduced, the available beams are sharpened to a certain extent, the Doppler spectrum purity is improved, and the speed measurement precision is improved by at least 5 times. For the Doppler radar, the speed measurement precision of the Doppler navigation radar is directly related to the effect of other inertial navigation combination navigation. Therefore, the overlapping beam antenna technology has important significance for high-precision Doppler speed measurement radars.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.
Claims (10)
1. A Doppler radar four-beam antenna for generating overlapped beams is characterized by comprising a radiation front unit and a feed unit;
the radiation array surface unit comprises N radiation waveguides which are parallel and uniformly arranged;
the feed unit comprises 4 feed waveguides; the 4 feed waveguides are arranged in a pairwise manner; two feed waveguides are arranged on the left side of the radiation array surface unit and feed to the left input end of each radiation waveguide; and the other two feed waveguides are arranged on the right side of the radiation array surface unit and feed the right input end of each radiation waveguide.
2. Doppler radar four-beam antenna for generating overlapping beams according to claim 1, characterised in that both ends of each of said feed waveguides are feed ports; the 4 feed ports of the two upper feed waveguides in the 4 feed waveguides arranged in pairwise rows are respectively used for feeding signals with the frequency of F1; the 4 feeding ports of the two feeding waveguides at the lower layer of the 4 feeding waveguides arranged in two-by-two rows are respectively used for feeding signals with the frequency of F2.
3. Doppler radar four-beam antenna for generating overlapping beams according to claim 1, characterised in that each radiation waveguide comprises a horn section at both ends and a radiating section in the middle; the wide end of the horn section contains 2 feed waveguides arranged in a row, and the narrow end of the horn section is connected with the radiation section; the horn section is used for realizing the transition of a signal from the feed waveguide to the radiation section; the radiating section is used for radiating signals.
4. Doppler radar four-beam antenna for generating overlapping beams according to claim 3, characterised in that the radiating section of the radiating waveguide is a narrow-edge slotted travelling wave slot radiating waveguide; the narrow edge of the waveguide is provided with a plurality of narrow edge cracks with the same length and width and staggered inclination angles, the interval between every two adjacent narrow edge cracks is the same, and the narrow edge cracks are symmetrically distributed on two sides relative to the central line of the radiation waveguide.
5. Doppler radar four-beam antenna for generating overlapping beams according to claim 2, characterised in that the feed waveguide is a narrow-edge slotted travelling wave slot waveguide; n narrow-edge slots with staggered dip angles are also formed in the direction of each feed waveguide close to the narrow edge of the radiation waveguide.
6. Doppler radar four-beam antenna for generating overlapping beams according to any of the claims 1-5, characterised in that the number of radiating waveguides N-22; the radiation waveguide cavity size is 17mm x 4 mm.
7. Doppler radar four-beam antenna for generating overlapping beams according to claim 6, characterised in that each radiation waveguide is opened with 36 narrow-sided slots with staggered inclination, the radiation slots being spaced apart by 11 mm.
8. Doppler radar four-beam antenna for generating overlapping beams according to claim 6,
the size of the feed waveguide is 18.75mm multiplied by 4mm, and 22 narrow-edge gaps with staggered dip angles are formed in the direction of each feed waveguide close to the narrow edge of the radiation waveguide; the feed waveguide slot pitch was 9 mm.
9. Doppler radar four-beam antenna for generating overlapping beams according to claim 6, characterised in that 8 feed ports of 4 feed waveguides are each fitted with a waveguide isolator.
10. Doppler radar four-beam antenna for generating overlapping beams according to claim 6, characterised in that the structural dimensions of the antenna are no more than 400mm x 200mm x 30 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121148425.9U CN215645032U (en) | 2021-05-26 | 2021-05-26 | Doppler radar four-beam antenna for generating overlapped beams |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121148425.9U CN215645032U (en) | 2021-05-26 | 2021-05-26 | Doppler radar four-beam antenna for generating overlapped beams |
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| Publication Number | Publication Date |
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| CN215645032U true CN215645032U (en) | 2022-01-25 |
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| CN202121148425.9U Active CN215645032U (en) | 2021-05-26 | 2021-05-26 | Doppler radar four-beam antenna for generating overlapped beams |
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- 2021-05-26 CN CN202121148425.9U patent/CN215645032U/en active Active
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